The mammalian olfactory system detects thousands of odors in the environment with precise discrimination. As the primary neuronal element in the olfactory system, olfactory sensory neurons (OSNs) are responsible for detecting odor molecules, transforming chemical information to electrical signals and sending these signals to the brain. Being exposed to the environment, olfactory epithelium has the remarkable ability to regenerate sensory neurons throughout life. While the molecular mechanisms involved in the regeneration of new neurons are being decrypted, little is known about the functional development of these sensory neurons, their response spectra during their maturation and lifespan, and the evolution of their physiological characteristics from immature to mature neurons. The long-term goal of this proposal is to address these critical issues using transgenic mouse lines expressing the green fluorescent protein (GFP) in the OSNs expressing a specific olfactory receptor. The specific aim of this project is to correlate the odorant responses of OSNs with defined receptors with their maturation stage and/or with their transduction machinery activities. The approach involves making patch-clamp recordings directly from the dendritic knobs of sensory neurons tagged with GFP in an intact epithelial preparation. The age and developmental stage of the neurons will be controlled by induced ablation and regeneration of mature neurons using OMP-DTR mice and by the length of their cilia. Carrying out this project will greatly enhance our knowledge about olfactory processing in general and provide the first physiological clues about the properties of developing olfactory neurons. [unreadable] [unreadable] [unreadable]